Phylogenetic analysis of hepatitis C virus isolates: correlation to viremia, liver function tests, and histology

Histological and virological features and follow-up of hepatitis C virus carriers with normal aminotransferase levels: the Italian prospective study of the asymptomatic C carriers (ISACC)

BACKGROUND/AIMS

To evaluate demographic characteristics, liver histology and virological features of hepatitis C virus (HCV) carriers with normal alanine transaminase (ALT) levels.

METHODS

A nationwide prospective study was started in 1997. Four Italian centres have participated in this study.

RESULTS

Eight hundred and eighty subjects entered the study. One hundred and eighty-nine (21.5%) were excluded during the follow-up because of ALT increase. Among the 691 patients with persistent ALT normality, 72% were females. An overall prevalence of genotype 2 was found (52%). Normal liver was found in 17% of the patients; 34% had minimal chronic hepatitis, 44% mild hepatitis, 4% moderate to severe hepatitis, and 1% had cirrhosis. Clinical and virological features did not differ between subjects with ALT flares and those with persistently normal ALT. Baseline ALT levels have no effects on liver histology and clinical outcome.

CONCLUSIONS

Many HCV carriers have significant chronic liver damage, although in the majority of them liver lesions are minimal or mild. Up to 60% of HCV carriers in Italy harbour non-1 HCV types. Current definition of HCV carriers with persistently normal ALT levels, based upon three normal ALT values over a 6-month period, is not adequate to discriminate between carriers with persistent ALT normality and those with transient biochemical remission. Longer follow-ups are needed.

Hepatitis C virus carriers with persistently normal aminotransferase levels: healthy people or true patients?

Since the discovery of hepatitis C virus, the availability of serological hepatitis C virus screening has led to the identification of many subjects with normal aminotransferase levels who are chronically infected by the hepatitis C virus. To date, the epidemiology and natural history of subjects with normal aminotransferase levels are far from being clarified. Further, whether subjects with persistently normal aminotransferase levels should routinely undergo liver biopsy is still extremely controversial, and benefit from interferon treatment in this group of patients is yet to be proven. On account of the consistent normality of aminotransferases, it is not easy to calculate the rate of persons with normal aminotransferase levels among chronic hepatitis C virus carriers, nor their prevalence in the general population. It has been estimated that up to 25% of patients with chronic hepatitis C virus infection have persistently normal aminotransferase levels (10% to 40%, according to different studies). Most studies showed a clear prevalence of females, ranging from 58% to 90%. Liver biopsy shows some degree of chronic liver disease in up to 80% of these subjects, although in the majority, histological damage is mild and probably does not progress to more severe liver disease, moreover, the progression to fibrosis is slower than in patients with elevated aminotransferase levels. Virological features of these subjects (hepatitis C virus genotype distribution, viral load, quasispecies diversity) do not differ with respect to patients with elevated aminotransferase levels although a higher frequency of non 1 hepatitis C virus types has been reported. To date, no biochemical or virological tools to assess the presence and severity of liver damage exist. Antiviral treatment with interferon may induce a long-term response in only a small proportion of hepatitis C virus carriers with persistently normal aminotransferase levels, and many patients develop aminotransferase-flare-up during or shortly after treatment. Thus, interferon or combination antiviral treatment of hepatitis C virus carriers with normal aminotransferase values should be avoided in clinical practice.